STUDY ON CONTROL MEASURES OF SURFACE SETTLEMENT IN LARGE DIAMETER SHIELD CONSTRUCTION IN SOFT SOIL LAYER
Aiming at the problem of surface settlement control in the construction of large-diameter mud-water shield in soft soil layer,the construction of two large-diameter mud-water shield tunnels in a cross-river tunnel in Hangzhou is taken as the background,through theoretical analysis and calculation and field practice verification,the excavation bin pressure setting,synchronous grouting mix ratio,shield attitude control and shield body synchronous filling which affect the surface settlement are studied,the technical measures and control points of surface settlement in the construction of large diameter mud-water shield in soft soil layer are summarized,such as setting the pressure of excavation chamber 0.2bar lower than the average value of static earth pressure and active earth pressure as the balance pressure,optimal mix ratio design of synchronous grouting slurry,parameter setting of shield shell grouting and timely monitoring,measurement feedback.The research results can provide a useful reference for the prevention and control of surface settlement in the construction of mud-water shield tunnel in soft soil layer.
large diameter slurry shieldsurface settlementpressure settinggrouting parameter
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